1. Field of the Invention
This invention relates to time keeping and, more particularly, to the use of digital time displays for general purpose time keeping. The term "general purpose", as applied to digital time displays or digital time keeping in context of the ensuing description, is used qualitatively to refer to the general time keeping needs and practices of ordinary individuals occupied with their usual activities on a day-to-day basis, as distinguished from specialized time monitoring procedures used in particular circumstances, e.g., scientific experiments, computer operations, games and sporting events, etc.
2. Description of the Prior Art
General purpose digital time displays have been available to consumers over the past several years in a variety of products, e.g. wrist watches, clocks, clock-radios and numerous other articles. Such displays generally consist of a horizontal array of hour and minute digits separated by a colon, with the hour digits positioned to the left and the minute digits to the right, and with the minute digits being driven to count values up from 01 to 59 and, one minute later, to reset to 00, with a simultaneous increase in the value of the hour digits to that of the next hour. On occasion, with liquid crystal type displays, second digits are also provided, positioned to the right of the minute digits and also driven to count seconds up from 01 to 59, with resetting to 00 one second later, when the value of the minute digits is increased to the next minute. In other instances, such as with light emitting diode type displays, switching is employed to display second digits alone, counted as described above but without a simultaneous display of hour and minute digits.
Although such displays and products have been commercially successful, they have not displaced completely, or even to a major extent, their analog counterparts and competition. The latter are based upon the conventional twelve-hour dial face with hour, minute, and optionally second, hands rotating through 360.degree. to indicate the time by the progressive positions of the hands relative to spaced markings applied along the dial perimeter. Many consumers, both prospective and actual, have found currently available general purpose digital time displays to be inconvenient, awkward difficult to use or otherwise objectionable in comparison to analog time displays, and often because of poorly perceived or definable reasons.
Although it appears to be commonly accepted that conventional general purpose digital time displays excel in informing the user of the present time at the moment of the readout, it is also recognized that burdensome mental calculations are required to translate that readout in the viewer's mind into grosser time contexts, e.g. the position of the precise time relative to a larger interval such as an hour or half hour, or how much time remains before the next hour or half hour, or how much time has passed or is to pass in relation to the occurrence of other exact times as previous or future references. Thus, conventional general purpose digital time displays suffer from the basic drawback of isolating the present time without also providing rapidly comprehendible indications of the larger time contexts which individuals ordinarily relay upon to carry out their general activities and for which analog time displays are far superior because of the graphic overall picture of gross time presented by their hand positions relative to the dial face markings. These and like problems in the use of conventional digital time displays have been described specifically, for example, in a survey reported in the November 1976 issue of Consumer Reports (Vol. 41, No. 11), a well known consumer products evaluation journal.